The present invention relates to improvements in a method and apparatus for making holes in the wrappers of rod-shaped smokers' products, for example, in the wrappers of filter plugs in filter cigarettes, cigarillos or cigars.
It is already known to perforate to wrappers of rod-shaped smokers' products in order to insure that cool atmospheric air will be mixed with hot tobacco smoke which flows from the lighted end of a smokers' product (hereinafter called cigarette or filter cigarette with the understanding, however, that smokers' products which can be treated in accordance with the method and in the apparatus of the present invention may also constitute plain or filter tipped cigars, cigarillos, cheroots as well as cigarettes of the type known as papyrossi). The admission of atmospheric air into the stream of hot tobacco smoke is desirable and advantageous because cool atmospheric air can influence the nicotine and condensate contents of tobacco smoke. However, the wrappers of cigarettes cannot be perforated at random, i.e., it is desirable to provide an apparatus which is capable of insuring that each and every cigarette will admit identical quantities of atmospheric air as well as that the apparatus will allow for adjustment of permeability of the wrappers, e.g., when a manufacturer wishes to change the quantity of inflowing air and/or when the permeability of cigarette wrappers exceeds or is less than an optimum permeability. Heretofore known perforating apparatus cannot meet such requirements.